You need to finalize your phone, otherwise you get configuration error.
Finalization = Completing flashing operations and storing basic settings that phone needs to properly operate [i.e. security certificates, (and this is why phone displays "configuration error" if it is not properly done)].

Note: MAIN and FS HAVE to be the same software version
MAIN R1BC002
FS R1BC002
Customization has to be same region as FS, in this case
FS = EU5 (EUROPE_5)
Customization =CDA102338/50 ( EUROPE_5 Sunrise Switzerland)
Look at the point 4) Customizing your phone in this tutorial
XS++ 3.1 Guide-Flashing,Customizing,Recovering - Top Sony Forums